Black corals (Antipathes spp.)

Kingdom

Animalia

Phylum

Cnidaria

Class

Anthozoa

Order

Antipatharia

Family

Antipathidae

Genus

Antipathes (1)

Listed on Appendix II of CITES (1).

Antipathes, meaning "against suffering", are corals that have been harvested for centuries to create charms and medicines, believed to have the power to ward off evil and injury (2). Antipathes species belong to the order Antipatharia, the black corals, which are named for their black or brownish flexible skeleton (2) (3). They possess distinctive tiny spines on the surface of the skeleton, and thus are sometimes also referred to as “little thorn corals” (2). Antipathes corals exhibit very diverse morphology; colonies can be sparsely or densely branched or bushy, with branches of varying length, arranged irregularly or with bilateral symmetry (4). Species also differ in their colour; the living tissue may be black, red, orange, brown, green, yellow, or white (2). Each polyp possess six, non-retractable tentacles that are armed with stinging cells (2).

The range of Antipathes corals is not clear.

Antipathes corals generally prefer deeper water with current (3).

Unlike reef-building corals, many black corals do not possess the symbiotic algae, zooxanthellae, within their tissues. They are therefore not restricted to shallow, sunlit waters where the zooxanthellae can photosynthesise, and instead are able to inhabit great depths and the dark waters of caves or under ledges (2). However, lacking zooxanthellae means that the coral must obtain nutrients by another method; black corals are carnivores and capture zooplankton in their tentacles as ocean currents move over the polyps (2).

Relatively little is known about the life cycle and reproduction of black corals. This is partly due to the depths which they inhabit, making it difficult to undertake research. An Antipathes colony may live for over 70 years (2) (5).

Black coral has been harvested for centuries, as a charm and a medicine, by people of many cultures who believe that black coral has the power to ward off evil and injury (2) (6). Today, black coral is still valued in jewellery and collection of these long-lived corals may threaten their survival (2). Antipathes corals also face the same threats that are impacting coral reefs globally. It is estimated that 20 percent of the world’s coral reefs have already been effectively destroyed and show no immediate prospects of recovery, and 24 percent of the world’s reefs are under imminent risk of collapse due to human pressures. These human impacts include poor land management practices that are releasing more sediment, nutrients and pollutants into the oceans and stressing the fragile reef ecosystem. Over-fishing has ‘knock-on’ effects that results in the increase of macro-algae that can out-compete and smother corals, and fishing using destructive methods physically devastates the reef (7).

Antipathes corals are listed on Appendix II of the Convention on International Trade in Endangered Species (CITES), which means that trade in this species should be carefully regulated (1). Antipathes corals will form part of the marine community in many marine protected areas (MPAs), which offer coral reefs a degree of protection, and there are many calls from non-governmental organisations for larger MPAs to ensure the persistence of these unique and fascinating ecosystems (7).

This information is awaiting authentication by a species expert, and will be updated as soon as possible. If you are able to help please contact: arkive@wildscreen.org.uk

Asexual reproduction: reproduction that does not involve the formation of sex cells, such as sperm and eggs. Asexual reproduction only involves one parent, and all the offspring produced by asexual reproduction are identical to one another.

Budding: type of asexual reproduction in which new individuals develop from the parent organism, forming a swelling similar in appearance to a bud. The ‘bud’ slowly separates from the parent as it grows.

Colony: relating to corals: corals composed of numerous genetically identical individuals (also referred to as zooids or polyps), which are produced by budding and remain physiologically connected.

Larvae: relating to corals: the stages of development before settlement on the reef. Larvae are typically very different in appearance to adults; they are able to feed and move around but usually are unable to reproduce.

Photosynthesise: Photosynthesis is ametabolic process characteristic of plants in which carbon dioxide is broken down, using energy from sunlight absorbed by the green pigment chlorophyll. Organic compounds are produced and oxygen is given off as a by-product.

Polyps: typically sedentary soft-bodied component of Cnidaria (corals, sea pens etc), which comprise of a trunk that is fixed at the base; the mouth is placed at the opposite end of the trunk, and is surrounded by tentacles.

Symbiotic: describing a close relationship between two organisms. This term usually refers to a relationship that benefits both organisms.

Zooplankton: floating or weakly swimming animals, many of them microscopic, that drift with water currents, particularly near the surface of the sea.